Digitoxin prolongs survival of female rats with heart failure due to large myocardial infarction.

Abstract

BACKGROUND: We analyzed whether digitoxin affects the survival of rats with congestive heart failure. METHODS AND RESULTS: The influence of digitoxin (0.1 mg.100 g.day, orally) on the survival of infarcted female rats (n=170) randomized as Control Infarcted (CI, n=85) or Digitoxin (D, n=85) was evaluated for 280 days. Mean survival was 235+/-7 days for CI and 255+/-5 days for D (log-rank test: P=.0602). Digitoxin did not affect survival in rats with congestive heart failure from myocardial infarction <40% of the left ventricle, but did prolong survival in rats with infarction >or=40%. The log-rank test defined higher mortality (P=.0161) in CI >40% (56%) than in D >40% (34%), with a hazard ratio of 2.03. Pulmonary water content and papillary muscle mechanics were analyzed in CI (n=7) and D (n=14) survivors. Significant differences were observed regarding pulmonary water content (CI: 82+/-0.3; D: 80+/-0.3%; P=.0014), developed tension (CI: 2.7+/-0.3; D: 3.8+/-0.3g/mm(2); P=.0286) and +dT/dt (CI: 24+/-3; D: 39+/-4 mg mm(2).s; P=.0109). CONCLUSION: In conclusion, long-term digitoxin administration reduced cardiac impairment after myocardium infarction, attenuated myocardial dysfunction, reduced pulmonary congestion, and provided the first evidence regarding the efficiency of digitoxin in prolonging survival in experimental cardiac failure.